Caisson.



No. 888,479. PATENTED MAY 26, 1908.

o. a. EDWARDS, JR.

GAISSON.

APPLICATION FILED JULY 17. 1906.

5 SHEETS-SHEET 1.

W1 in wow m: NORRIS PETERS cm, wasmmzron, n c

No. 888,479. PATENTED MAY 26, 1908.

o. c. EDWARDS, JR. OAISSON.

APPLICATION TILED JULY 17. 1906.

5 SHEETS-SHEET 2.

f ngs da #127 L9/ THE NORRIS PETERS C0 WASHINGTON, n c.

N0. 888,479.- PATENTED MAY 26, 1908.

- 0. c. EDWARDS, JR.

GAISSON.

APPLIOATION FILED JULY 1'1, 1906.

6 SHEETS-SHEET 3.

No. 888,479. PATENTED MAY 26, 1908.

o. o. EDWARDS, JR;

GAISSON.

APPLICATION FILED JULY 17. 1906.

5 SHEETS-SHEET 4.

i 6 I 6463 64 I 64 THE NORRIS PETERS ca, wAsumcmN. D- c.

OLIVER GROMWELL EDWARDS, JR., OF TROY, NEW YORK.

CAISSON.

Specification of Letters Patent.

Patented May 26, 1908.

Application filed'J'uly 17, 1906. Serial No. 326,622.

To all whom it may concern:

Be it known that I, OLIVER Cl EDWARDS, Jr., citizen of the UnitedStates, residing at Troy, in the county of Rensselaerand State of NewYork, have invented certain new and useful Improvements in Caissons; andI do hereby declare the following to be a full, clear, and exactdescription of the invention, such as will enable others skilled in theart to which it appertains to make and use the same.

This invention relates to improvements in caissons, and moreparticularly to a design of caisson especially adapted for economicalconstruction from concrete.

The primary object in view is the production of a concrete caisson sodesigned as to possess a maximum amount of strain withstanding-capacitywhile incorporating only a minimum amount of material, whereby a savingis obtained both as to the weight of the caisson and the expense ofproduction.

With this and further objects in view, the

invention com rises the combination of relatively thin inc osing wallsand a roof forming a working chamber, of stiffening trusses formedintegral with the side walls, and stiffening trusses for the roof.

The invention further comprises the combination with a caisson work ngchamber of stiffening trusses formed integral with the side wallsthereof.

The invention also comprises the cornbina tion with concrete caissonwalls, of a metallic truss forming a reinforcement for the cutting edgeof said wall.

The invention still further comprises certain other novel constructions,combinations and arrangements of parts as will be hereinafter fullydescribed and claimed.

In the accompanying drawing: Figure 1 is a top plan view of a caissonembodying the features of the present invention. Fig. 2 is an endelevation thereof, a fragment of a coffer dam being illustrated asmounted thereon. Fig. 3 is a longitudinal, vertical, central sectiontaken through Fig. 1 on the plane in dicated by line 33. Fig. 4 is atransverse, vertical, central section taken through the structureillustrated in Fig. 1 on the plane indicated by line 44: Fig. 5 is alongitudinal, vertical section through the structure illustrated in Fig.l taken on-the plane indicated by line 55, looking in the directionindicated by the arrow. Fig. 6 is a transverse, vertical section'throughthe structure disclosed in Fig. 1, taken on the lane indicated by line6-6 of Figs. 1, 3 an 5. Fig. 7 is a longitudinal, verticals'ectionthrough the structure illustrated in Fig. 1, taken on the planeindicated by line 77 and'looking in the direction indicated by thearrow, the parts being illustrated on an enlarged scale. Fig. 8 is asimilar section taken on the lane of'line 8-8 of Fig. 1 and looking inthe irection indicated by the arrow. Fig. 9 is a top plan view of afragment of the metallic reinforcement for the cutting edge. Fig. 10 isan end view of the same, the concrete walls and wall trusses and thelower chord of a chamber or wall truss being indicated by dotted lines.Fig. 11 is a view in side elevation thereof. Fig. 12 is an enlargeddetail view artly in elevation and partly in section of a fragment ofone of the caisson walls and roof and illustrating two of the wallpanels. Fig. 12 is an'enlarged, detail of one of the knee-braces of Fig.12. Fig. 13 is a sectional view in detail, taken on the plane of line1313 of Fig. 12. Fig. 14 is a similar View taken on the plane of line1414 of Fig. 12. Fig. 15 is a similar view taken on the plane of line1515 of Fig. 12. Fig. 16 is a similar view taken on the plane of line1616 of Fig. 12. Fig. 17 is a top plan. view of a fragment of one of thecorners of the caisson, indicating in end view the corner protectingangle plate and illustrating the supporting pins or bolts therefor. Fig.18 is a view in elevation of the same. Fig. 19 is a longitudinal,vertical section, similar to Fig. 5, but taken through a slightlymodified form of caisson. Fig. 20 is a transverse, vertical sectiontaken on the plane of line 2020 of Fig. 19 and looking in the directionindicated by the arrow. Fig. 21 is a longitudinal, vertical sectionsimilar to Fig. 19 of another modified'form of caisson. Fig. 22 is atransverse, vertical section taken onthe plane of line 2222 of Fig. 21and looking in the direction indicated by the arrow. Fig. 23 is a topplan view of another modified form of caisson. Fig. 2 1 is an end viewthereof, a fragment of cofi'er dam being indicated as mounted thereon.Fig. 25 is a longitudinal, vertical, central section taken on the planeof line 25-25 of Fig. 23. Fig. 26 is a transverse, vertical, centralsection taken on the plane of line 26-26 of Fig. 23. Fig. 27 is alongitudinal, vertical section taken on the plane of line 27-27 of Fig.23 and looking in the direction indicated by the arrow. Fig. 28 is atransverse, vertical section taken on the plane of line 2828 of Figs.23, and 27 and looking in the direction indicated by the arrow. Fig. 29is a top plan view of another modified form of caisson. Fig. 30 is alongitudinal, vertical, central section taken on the plane of line 3030of Fig. 29. Fig. 31 is a transverse, vertical, central section taken onthe lane of line 31-31 of Fig. 29. Fig. 32 is a ongitudinal, verticalsection taken on the plane of line 3232 of Fig. 29, looking in thedirection indicated by the arrow. Fig. 33 is a transverse, verticalsection taken on the plane of line 3333 of Figs. 29, 30 and 32 andlooking in the direction indicated by the arrow. Fig. 34 is a top planview of a further modified form of caisson. Fig. 35 is an end viewthereof. Fig. 36 is a transverse, vertical, central section taken on theplane of line 3636 of Fig. 34. Fig. 37 is a transverse, vertical,central section taken on the lane of line 3737 of Fig. 34. Fig. 38 is aongitudinal, vertical section taken on the plane of line 38*38 of Fig.34 and looking in the direction indicated by the arrow. Fig. 39 is atransverse, vertical section taken on the plane of line 3939 of Figs. 34and 36 and looking in the direction indicated by the arrow. Fig. 40 is atop plan view of a further embodiment of the present invention. Fig.

v 41 is a transverse, vertical, central section therethrough, a fragmentof a coffer dam being illustrated as being mounted upon the caisson.Fig. 42 is a horizontal section taken on the plane indicated by line4242 of Fig. 41. Fig. 43 is a top plan view of a further modification.Fig. 44 is a longitudinal, vertical section taken on the plane of line4444 of Fig. 43 and looking in the direction indicated by the arrow.Fig. 45 is a transverse, vertical section taken on the plane indicatedby line 4545 of Figs. 43 and 44 and looking in the direction indicatedby the arrow.

\Vhile I have illustrated in the accompanying drawingsv a fewmodifications showing several different embodiments of the presentinvention, a careful study of the drawings will disclose the fact thatthroughout all of the structures there is found a broad conception ofthe use of comparatively thin walls strengthened by stiffening trusseswhich are cast integral with the walls. This principle of constructionenables the use of concrete and the production of strong, rigid wallstherefrom capable of resisting all the strains to which a caisson isusually subjected, the objection to the weight of the concrete beingobviated by the comparative thinness of the walls. The corners of thecaisson and the cutting edge thereof are also stiffened and protected bymetal devices hereinafter fully described.

Perhaps the simplest form of caisson embodying the features of thepresent invention illustrated in the accompanying drawings is seen inFigs. 40, 41 and 42, but for the purpose of making clear the adaptationof the invention to the larger types of caisson, I shall describe theconstruction illustrated in Figs 1 to 16 inclusive as an exemplificationof the invention.

Referring to the drawings by numerals, l1 indicates the vertical sidewalls, and 22 the vertical end walls of the caisson. The said side andend walls are preferably cast of concrete, a roof 3 cast integral withsaid walls completing a caisson working chamber. It will be noted thatthe said vertical walls and the roof are made relatively thin and castintegral; with each of the side walls is a truss 4, and cast integralwith each of the end walls is a similar truss 5, said trusses beingarranged for stifiening and strengthening the respective Walls. Each ofthe trusses 4 and 5 may be constructed in any preferred form, and I haveshown, for the purpose of illustration, each of said trusses composed ofan upper chord 6 and a lower chord 7, the said chords being connected atintermediate points by vertical studs 8-8, and also connected byinclined braces 9-9 interposed between the studs 8. Each of the saidchords, studs and braces is cast integral with the respective verticalwall, and the truss formation produced-thereby renders the wall firm andrigid and capable of withstanding enormous strains, while the weight ofthe wall is not materially increased over that of the comparatively thinsolid wall. As seen in Figs. 3 and 4, 1 preferably further strengthenthe structure by longitudinal and transverse trusses extending entirelyacross the space of the working chamber and having their ends castintegral with the vertical walls. Each of the trusses 10 and 11 ispreferably made up of an upper chord formed integral with the roof, alower chord and integral, vertical studs and inclined braces connectingthe upper and lower chords.

The roof 3 is made comparatively thin and is stiffened by longitudinaland transverse trusses produced by a longitudinal beam 12 and transversebeams 13-13. The beam 12 is interrupted at various points along itslength by solid portions l414 of the roof at the points of the openings1515, the said solid portions being mere thickened parts of the roof forstrengthening the roof about the openings 15. The openings 15 areprovided for v the spoil shafts and main shaft, and each of saidthickened portions is connected with a contiguous transverse beam 13 byparallel, longitudinal beams 1616, so that the beam 12 may be consideredcontinuous when the beams 16 and the solid portions 14 are considered asparts of the beam 12. Arrangedparallel to the beam 12 and extendinglongitudinally of the caisson are beams 1717, which beams 17 with thebeam 12 constitute roof forming a cofferdam structure.

stiffening trusses, all of said beams being cast integral with the roof,and the cross beams 13 may be considered the connecting braces of thetrusses, said cross beams and longitudinal beams producing roof panels1818. Each of the beams 12 13 and 17 is provided at each side withstiffening and strengthening, relatively small knee-braces l8 Bypreference, I continue the walls 11 ulpwardly beyond the roof, as at 11,and a so continue the walls 2 upwardly beyond the roof, as at 22, thesaid walls 1 and 2 Of course, the cofler dam structure may be made ofany required depth, but by preference a wooden cofferdam 1 9 is mountedupon the walls 1 and 2" so that said walls are preferably extendedupwardly only a relatively short distance. As seen best in Figs. and 6,each of the walls 1 is provided with a stiffening truss 20, similar inconstruction and arrangement to trusses 4, and each of the walls 2 isprovided witha stiffening truss 21 similar in construction andarrangement to the trusses 5. Longitudinal trusses 2222 extend parallelto each other throughout the length of the coffer dam and connect theend walls thereof, and transverse trusses 2323 extend across the cofferdam and connect the side walls thereof. Each of the trusses 23 issimilar inconstruction and arrangement to the trusses 11, except, ofcourse, that the lower chord is formed integral with the roof instead ofthe upper chord and the lower chords of the trusses 22 are formed fromthe beams 17-17. The upper and lower chords of the lon itudinal trusses22 are connected by vertica studs and inclined braces similarly to thebraces of the trusses 10. The transverse trusses 23 are constructed andar ranged similarly to the trusses 11, except that the lower chords areformed integral with the roof instead of the upper chords, i

the same form of inclined braces and vertical studs being provided. Thetrusses 11 preferably, though not necessarily intersect the trusses invertical ali-nement with the points of intersection of the trusses 23with the trusses 22, and all the said trusses may if preferred be tiedtogether by vertical tie rods extending throughout thelength of the vertical posts produced by the intersection of the trusses, as clearly seenin Fig. 7. I ropose also to tie the various other parts of the caissonby metallic rods or bars, and to stiffenthe braces and studs 0f thetrusses as well as other arts of the caisson bysuitable metallic reinorcement as I may find desirable. I have illustrated the bars arrangedcentrally of the braces, and only one bar is shown for each brace, butit is, of course, obvious that any arrangement and any preferred numberof bars may be employed as found desirable.

of the roof for the stiffening of the same produces panels and it will,of course, be obvious that the wall trusses also produce panels, and Ihave shown a detail construction of one of the wall panels in Figs. 12to 16 inclusive. I have omitted such detail construction from theillustrations in Figs. 1 to 8 inclusive, for the purpose of clearness,and it is to be understood that the detail construction shown in Figs.12 to 16 inclusive is to be employed if desired in connection with allof the wall panels.

Each of the inclined braces and vertical studs as well as the contiguouschords of each of the wall panels may be stiffened and strengthened by acontinuous knee-brace 24 extending about the entire panel, or ifpreferred, the knee-brace need not be made continuous but may be formedonly at intervals, as indicated at 2525. When the kneebraces 25 areemployed, they are preferably made of a height equal to the thickness ofthe particular brace or chord, but when the kneebrace-24 is-utilized,the same need not necessarily be extended to the full height'of thebrace or chord. Of course, if preferred the '.knee-brace 25, as seen inFig. 13, may be made of a less height than the width ofthe member whichit braces. As seen in Fig. 12, the knee-braces 25 may if preferred bethemselves strengthened and braced by fillings 2626, the said fillings26 being of trihedral angle form, filling the cornerroduced by thejuncture of the face of the nee-brace with the face of the braced memberand with the face of the vertical wall.

It is to be noted that all of the knee-braces referred to are merevariations of the kneebrace seen at 24, the braces 25 which are notprovided with the trihedral angle fillings being merely fragments of thecontinuous kneebrace, and the knee-braces 25 provided with the fillings26 being the same fragments with additional fragments arranged foradvantageously bracing the particular member with which the givenknee-brace is connected. It is to be observed particularly from Figs. 14and 16 that the knee-brace 25 may assume a form larger than a mereincline filling, and may be provided with a body portion 25 whichextends to the full width of the member braced and projects into thepanel, and the knee-brace proper 25 connects the wall with the bodyportion 25. The form of knee-brace embodying the body portion 25, ofcourse, possesses greater rigidity and aids more materially in bracing amember with which it is connected, although the use of the body portion25 necessarily adds to the weight of the construction.

As seen in Figs. 17 and 18 each of the cor- I ners of the caisson isprotected by an angle plate 26. Each of the plates 26 is preferablyformed flush with the outer surface of the has been notedabove that thetrussing 1 caisson wall, and is also preferably firmly secured in placeby means of bolts or pins 2727 which are anchored in the material of thecorner of the caisson, the heads of the pins or bolts being embedded inthe material of the plate so as to lie flush with the exposed facethereof. The plates 26 guard the corners during the descent of thecaisson and prevent ury to such corners which might occur from contactwith rocks.

The cutting edge of the caisson is provided With a metallicreinforcement 28. The said reinforcement is seen in detail in Figs. 9 to1 1, and consists of a horizontal truss 29 with a vertical truss 30depending therefrom. The truss 29 is made up of chords 3131 and anintermediate connecting and bracing web 3232. To the web 32 is securedan angle plate 33 which constitutes the upper chord of the truss 30. Apair of angle plates 34 34 constitutes the lower chord of the said truss30 and the said chords are connected by an intermediate open web 35. Aplate 36 is secured to the angle plates 34 and extends the full width ofthe two plates, or if preferable it may be wider than the angle plates.Suitable reinforcing bars 3737 are arranged at any desired points andsecured to the trusses 29 and 30 and extend in various directions withinthe concrete forming the walls, the wall trusses, and chamber trusses ofthe caisson. The horizontal truss stiffens the chamber wall and walltruss against the inward and outward pressure of the surrounding earthand Water, and of the chamber air, respectively, and the vertical trussfurnishes the necessary tensile strength to the lower chord of the walltruss, the open webs of both trusses permitting an intimate bond betweenthe trusses and the surrounding concrete. The plate 36 materiallyincreases the ca 1pacity of the cutting edge for penetrating ardmaterials without being materially damaged thereby.

From the foregoing it will be seen that the present inventioncomprehends the production of a comparatively light and yet excetionally strong and rigid caisson, of relatively cheap material, whichcaisson has the advan tage of being capable of being used as a part ofthe finished structure without danger of destruction or materialdeterioration from age, marine borers or the action of water, and itwill be further noted that the various other embodiments of theinvention illustrated incorporate the general principles present in thecaisson above described.

Owing to the close similarity between the caisson above described andthe several modifications, only those features in the modificationswhich difier from the above described structure will be described indetail, and the remaining-features will be simply referred togenerically, as they may be readily understood by reference to theforegoing description.

It is to be observed that the structure above described is provided witha roof stiffening truss arranged on top of the roof with no horizontaltruss formation on the under face of the roof, and the reason for thisis that is is difficult to fill with concrete any pocket or recess soarranged as to be filled with air and have the point of discharge of theair out ofi before the pocket is completely filled. However, anyordinary pocket may be filled with grout or concrete by the use of aforce pump and a pipe extending into the pocket, which pipe is removedafter the pocket has been filled. It will thus be seen that while thepocket is objectionable it is not fatal to a construction, andtherefore, when it is desired to make the roof thinner than the roof ofthe structure above described, I propose to construct the caisson asillustrated in Figs. 19 and 20, wherein is shown a roof provided with alongitudinal beam 38 formed integral at its ends withthe end walls ofthe caisson and braced at each end by a knee-brace 39. Transverse beams4040 are provided beneath the roof, and some of the said beams 40 arebraced at their ends by knee-braces 41-41, all of the said beams 40being formed integral at their ends with the side walls of the caisson.Of course, all of the beams 40 and the beam 38 are formed integral withthe roof, and said-beams constitute a stiffening truss for the roofarranged beneath the same. All the other features of the structureillustrated in Figs. 19 and 20 are common to the structure abovedescribed.

In Figs. 21 and 22 I have illustrated a structure corresponding indetail to the structure seen in Figs. 1 to 16 inclusive, eXce t that thelongitudinal trusses 42-42 of tfie coffer dam and 43-43 of the workingchamber, and the transverse trusses 4444 of the coffer dam and 4545 ofthe working chamber have each one chord incorporated as an integral partof the roof. or in other words that chord of each truss next to the roofhas no separate entity from the roof, but the roof is made to serve thefunction of the chord and for this reason is made slightly thicker thanotherwise.

In Figs. 23 to 28 inclusive Ihave illustrated a caisson whose roof istrussed in the coffer dam similarly to the truss formation shown inFigs. 1 to 16 inclusive, the longitudinal and transverse beams beingbraced at their ends by knee-braces 4646. In this construction, however,the coffer dam consists of longitudinal side trusses 4747 and transverseend trusses 48-48, said side and end trusses being connected with theroof by vertical posts or studs 49-49, which posts or studs are formedintegral with the kneebraces 46. The end trusses 48 are connected bylongitudinal trusses 5050, and the longitudinal trusses 47 areZconnectedby transverse trusses 51-51. The trusses 50 and 51 are of the simplestpossible construction, and are provided with top and bottom chords andvertical studs only, the inclined braces being omitted. The coiier damstructure proper 52 is arranged to inclose the trusses 4:7 and 48 and isprovided with an upper wale 53 resting upon the up er chords of thetrusses 47 and 4.8 and is al lower wale 54 resting upon the roof andembedded in the material of the vertical posts 49. The wales 53 and 54are secured firmly in place by bolts or pins passed through the wa esand embedded in the contiguous concrete. The cofier dam proper is thusfirmly sustained upon the caisson, and the caisson is at the, same timematerially reduced in weight. The working chamber of the caisson is madeof relatively thin vertical walls formed with the end wall trusses 55-55and side wall trusses 56-56, each of the said end and side wall trussesbeing made up simply of a lower chord and vertical posts 57-57connecting such chord with the roof, the roof serving as the upper chordfor all of the side and end wall trusses. The vertical posts or studs 57are braced by knee-braces 58-58 formed integral with said studs and withthe roof. Longitudinal trusses 59-59 are ar ranged within the workingchamber and similar transverse trusses 60-60 are arranged therein, eachof the trusses 59 and 60 consisting simply of upper and lower chordsconnected by vertical studs 61-61. The upper chord of each of saidtrusses is, as indicated in the drawings, formed integral with the roofand is braced at each end by a kneebrace 62 which is also formedintegral with the roof and is in addition formed integral with thevertical walls of the working chamber.

In Figs. 29 to 33 inclusive, I have illustrated a further embodiment ofthe resent invention incorporating substantia y the same features shownin and described with respect to Figs. 1 to 16 inclusive, the onlyimportant difference being that the roof trusses are, in additiontobeing constructed of the longitudinal and transverse beams, formedwith diagonal braces 63-63 constructed and arranged similarly to the arrangement of diagonal braces in the side wall stiffening trusses, seenbest in Fig. 8. This produces a light roof and gives great strengthagainst any racking of the caisson in a horizontal plane, such as itmight receive while bein towed in rough water. It is to be noted thatthe openings 64-64 for the spoil shafts and man shafts are so disposedthat the weight of the shafts will be transmitted directly to thelongitudinal trusses and to the two transverse coffer roof beams, sothat there will be no danger of the concrete cracking around the shaftsdue to any slight swaying of the shafts. It. will be observed that thediagonal braces of the longiso provided with awalls with the end tudinaltrusses in the cofier dam and also the diagonal braces of thelongitudinal trusses in the working chamber are disposed in suchpositions as to appear at right angles to the inclined braces in thewall trusses. But it is, of course, obvious that this is a mere matterof choice of arrangement for obtaining advantageous transmission ofstress under some particular conditions.

In Figs. 34 to 39 inclusive, I have illustrated another embodiment ofthe invention in which the concrete walls are extended above the rooffor producing a coiier dam, the upright walls of the caisson beingformed relatively thin and strengthened by wall trusses. The roof alsois strengthened by stiffening trusses, the form of the roof trussesdiffering from those illustrated in Fig. 1 only in that the spoil shaftand man shaft openings 65 are formed rectangular instead oi circular,and the solid, thickened portions of the roof about thesaid openingsbeing formed to accommodate the rectangular apertures.

I have not illustrated the longitudinal and transverse beams forming theroof trusses as being provided with knee-braces such as are seen at 18in Fig. 1, but it is, of course, ob-

vious that such knee-braces may be employed if desired. The workingchamber is formed with longitudinal trusses 66-66 and transverse trusses67-67. Each of the trusses 66 and 67 consists simply of an upper and alower chord and vertical braces or studs connecting the same, the upperchord being formed integral with the roof. The side and end walls of theworkingchamber are formed with stiffening trusses constructed similarlyto the trusses 66 and 67. Some of the vertical studs of the wall trussesare strengthened'by knee-braces 68 (see Fig. 38), each of theknee-braces being formed integral with the roof and with its respectivestud. By reference the lower end of each of the vertical studs isfurther strengthened by relatively small A knee-braces 69-69 formedintegral with the lower chord of the respective truss, with therespective vertical stud. Those vertical studs which are not providedwith the knee-braces 68 are provided with a larger knee-brace 70. Thebraces 70, as indicated in cross section in Figs. 36 and 37 and in fulllines in Figs. 38 and 39, extending from the roof down to the lower edgeof the lower chord, and are formed integral with the roof, the verticalstud, and the chord, the vertical stud, of course, being formed integralwith the upright wall. The knee-braces 68 and 70 serve to withstand anyinwardly crushing strains, and are especially designed to preventlateral swaying oi the wall trusses due to the impact of a wave. Inorder to further strengthen the upright walls, each of the cornersproduced by the juncture of the side walls and with the roof is and alsoformed integral provided with a filling 71 which is of approximatelytrihedral angle form, the corners of the inner face of each of saidfillings being cut away, as indicated in dotted lines in Fig. 34, inorder to produce the required formation for the wall trusses- The cofferdam walls are strengthened by Wall trusses constructed like the walltrusses of the working chamber walls, and the cotter dam is furtherstrengthened by longitudinal trusses 7272 and by transverse trusses7373. The trusses 72 and 73 consist simply of upper and lower chordsconnected by vertical studs, the lower chord of each truss being formedintegral with the roof. The vertical studs of the wall trusses arebraced by knee-braces, some of the said vertical studs being braced byrelatively small kneebraces 74 which extend inwardly and are formedintegral with the roof of the caisson and with the respective verticalstuds. Those studs which are not braced by the relatively smallknee-braces 74 are braced by relatively large knee-braces 75-7 5, eachof the braces 75 being formed integral With the roof and extendingupwardly to the top of the upper chord of the respective wall truss, thesaid knee-brace bein of course, formed integral with the vertical studand the stud in turn being formed integral with the upri ht wall. I haveonly shown a comparative y small number of the knee-braces 75 and a relatively larger number of the small kneebraces 74, but, of course, itisobvious that as many of the braces 75 will be employed as are founddesirable. It is to be noted that each of the vertical studs of the walltrusses of the cofier dam is braced by relatively small knee-braces 7676 at each end, each of said knee-braces being formed integral with therespective stud and also formed integral with the contiguous chord.

While the diagonal braces in the various trusses are not illustrated inconnection with Figs. 34 to 39 inclusive, it is obvious that such bracesmight be employed, and in fact I propose to employ the same inconnection wlth the caisson illustrated in the said figures Whenever thecaisson is to be subjected to ex ceptional service' The diagonal bracesin the roof trusses may also be used in the construction seen in Figs.34 to 39 inclusive, and the working chamber roof truss, indicated inFigs. 19 and 20, may be utilized in the caisson seen in Figs. 34 to 39inclusive when found desirable. A caisson constructed as illustrated, inFigs. 34 to 39 inclusive, formed with the inclined braces for the walltrusses and for the transverse and longitudinal trusses, and also forthe roof truss, and formed with a roof truss in the working chamber-would incorporate all of the several details of the present invention,and in considering the appended claims it is desired that suchaficonstruction be understood to be the preferred embodiment of thepresent invention, and that the several modified constructionsillustrated and described, have been disclosed for the pur ose of makingclear the several details and or reventing confusion by the showing of amul tiplicity of parts in a single construction, it being understood,ofcourse, that the corner plates seen in Figs. 17 and 18 and the cuttingedge reinforcements seen in detail in Figs. 9 to 11 inclusive areemployed regardless of the detail design of the articular caisson.

As s owing one of the simplest forms of the present improved caisson,reference may be had to Figs. 40 to 42 inclusive, wherein is seen arectangular caisson chamber of relatively small dimensions, the size ofthe cais-' son being such as to obviate the necessity for trusses withinthe working chamber. The roof is trussed by beams 77 arranged to connectthe diagonally opposite corners, but interru ted intermediate theirlength by the circul ar thickened or solid portion of the roof 78, whichproduces roof panels 797 9 and is arranged to support the shaft 80. Thecircular thickened ortion 78 is, of course, formed integral with thebeams 77. The u right walls of the caisson are made relative y thin, andare strengthened by wall trusses formed from a lower chord 81 andvertical 9 connecting studs 8282 which extend to the roof, the roofserving as the upper chord, and the corner studs 82 being meretriangular fillings. As indicated in Fig. 41, the cofler dam is mounteddirectly upon the caisson and may be anchored thereto in any suitablemanner.

In Figs. 43 to 45 inclusive, I have illustrated a further embodiment ofthe simpler form above described with reference to Figs. 40 to 42inclusive. In the structures seen in Figs. 43 to 45 I have utilized thesame form of wall trusses with knee-braces 8484 for each of the ends ofeach of the vertical studs of the wall truss, each knee-brace 84 beingformed integral with the respective stud and with the contiguous chordor with the roof as the case may be, the roof itself serving as theupper chord. Each of the vertical studs is further braced againstinwardly acting strains by a knee-brace 85 arranged at its up per endand formedintegral with the roof and with the respective knee-brace.

Having thus fully described my invention, what I claim as new and desireto secure by Letters Patent is 1. In a caisson, the combination withupright walls and a roof, of wall trusses arranged contiguous to thewalls and formed integral therewith for strengthening the same.

2. In a caisson, the combination with upri ht inclosing walls, oftrusses arranged par alIel to and connected with the walls and formedintegral therewith throughout their length. e

3. In a caisson, the combination with upright inclosing walls, of atrussfor each of said walls formed integral therewith.

4. In a caisson, the combination with upright inclosing walls, of a walltruss for each of said walls, each of said trusses extendin throughoutthe length of its respective Wal and being connected therewith.

5. In a caisson, the combination with inclosing concrete walls, ofconcrete trusses cast integral with said walls throughout their length.

6. In a caisson, the combination with upright Walls and a roof formingthe working chamber, of wall trusses formed integral with the uprightwalls throughout their length, and arranged for producing asubstantially continuous truss about the inner faces of the uprightwalls.

7. In a caisson, the combination with upright walls and a roof forming aworking chamber, of bracing means for said walls and roof extendingacross the space of the working chamber, and trusses connected throuhout their length with the said upright walls.

8. In a caisson, the combination with inclosing walls and a horizontalroof therefor, of a horizontally disposed truss connected with the roofand arrangedfor strengthening the same.

9. In a caisson, the combination with inclosing walls and a rooftherefor, of a truss having all of its members formed integral with theroof.

10. In a caisson, the combination with inclosing walls and a rooftherefor, of a truss disposed horizontally with one of its facesconnected with the roof and its ends connected with the inclosing walls.

. the said trusses being formed integral with the roof.

13. In a caisson, the combination with inclosing walls and a rooftherefor, of braced roof beams arranged beneath the roof and disposedwith all of their members formed integral with said roof.

. 14. In a caisson, thecombination with inclosing walls and a rooftherefor, of braced roof beams arranged beneath the roof and each havingone of its faces lying parallel to the plane of the under face of theroof, said beams being connected with the roof.

15. In a caisson, the combination with in closing walls of a rooftherefor, and longitudinal beams formed integral with the roofthroughout their length and integral with the Walls at their ends.

16. In a caisson, the combination with inclosing walls and a roof, oftransverse beams formed inte ral with the roof and connected with the wals at their ends. 7

17. In a caisson, the combination with inclosing walls and a rooftherefor, longitudinal beams formed into ral with said roof, andtransverse beams a so formed integral with the roof and intersecting thelongitudinal beams,

1.8. In a caisson, the combination with inclosing walls and a rooftherefor, of" a strengthening beam extending across the inclosureproduced by said walls and connected with said roof, and knee-bracesconnected to the beam and to theroof.

- 19. In a caisson the combination with inclosing Walls and a roof, of abeam extending across the inclosure produced by said walls and formedintegral with the roof throughout its length, and knee-braces formedintegral with the said beam and also formed integral with the roof.

20. In a caisson, the combination with inclosing walls and a roof, of astrengthening beam arranged above the roof and extending across theinclosure produced by said walls, the said beam being formed integralwith the roof.

21. In a caisson, the combination with inclosing walls and a roof, of abeam extending across the inclosure produced by said walls, and bracingmeans formed integral with the roof and also formed integral with saidbeam.

22. In a caisson, the combination with inclosing walls and a rooftherefor, of wall trusses formed integral with the walls throughouttheir length, the several members of each of said trusses being providedwith strengthening knee-braces.

23. In a caisson the combination with inclosing walls and a roof, ofwall trusses connected with the walls for strengthening the same, andknee-braces connected with the walls and with said trusses.

24. In a caisson, the combination with inclosing walls and a rooftherefor, of a wall truss for each of said Walls, each of said trussescomprising upper and lower chords connected with the respective wallsand braces connecting the chords, each of said braces and chords beingprovided with kneebraces connected with the respective wall.

25. In a caisson, the combination with inclosing walls and a roof, of atruss for each of said walls comprising upper and lower chords, andmembers connecting said chords and knee-braces connecting said memberswith the respective wall.

26. In a caisson, the combination with inclosing walls and a rooftherefor, of parallel, longitudinal beams arranged above and connectedwith the roof and constituting the chords of a truss, transverse beamsconnecting said longitudinal beams, and diagonal braces connecting saidlongitudinal beams.

27. In a caisson, the combination with inclosing walls and a roofproducing a working chamber, of upright walls extending above the roofproducing a cofferdam, and wall trusses formed integral throughout theirlength with said coffer dam walls.

28. In a caisson, the combination with inclosing walls and a roofforming a working chamber, of vertical walls extending above said roofand producing a coifer dam, vertically disposed truss'es arrangedparallel to the coffer dam walls and connected therewith throughouttheir length.

29. In a caisson, the combination with inclosing walls and a roofroducing a working chamber, of upright wa ls extending above the roofproducing a coffer dam, vertically dis osed trusses arranged parallel tothe several coffer dam walls and formed integral therewith, the saidcofl er dam walls and trusses being cast from concrete.

30. In a caisson, the combination with inclosing walls and a roof, ofwall trusses connected with said walls for strengthening the same andbraces connecting the said trusses with the said roof.

31. In a caisson the combination with inclosing walls and a roof, oftrusses cast integral with said walls throughout their length, andbraces cast integral with the trusses and with said roof.

32. In a caisson, the combination with inclosing walls and a rooftherefor, of a wall truss for each of said walls cast integral with thewall throughout its length, each of said trusses being provided withvertical studs, and knee-braces cast integral with said vertical studsand also integral with said roof.

33. In a caisson, the combination with inclosing walls, of a roofarranged intermediate the height of said walls producing a workingchamber, wall trusses disposed for strengthening the said walls andknee-braces connecting said trusses with the roof.

34. In a caisson the combination with inclosing walls, of a rooftherefor, wall trusses arranged above said roof, and knee-bracesconnecting said wall trusses with the roof.

35. In a caisson, the combination with inclosing walls and a rooftherefor, of wall trusses extending above said roof and each comprisingparallel chords and connecting studs, and bracing means connecting thesaid studs with the roof.

36. In a caisson, the combination with inclosing walls and a roof, ofwall trusses arranged about and connected with said roof, andknee-braces connected with the roof and with said trusses and extendingfrom the roof to the outermost chords of the trusses.

37. In a caisson the combination with inclosing walls and a roof forminga working sea me chamber, of a truss connected with one of said walls,and a knee-brace connecting said roof with the lower chord of saidtruss.

38. In a caisson the combination with inclosing walls and a roof, of awall truss connected with one of said walls, said truss being providedwith vertical studs, and a kneebrace formed integral with the roof andintegral with one of the studs of said truss, and extending from theroof to the outermost chord of the truss.

39. In a caisson, the combination with inclosing walls, of a rooftherefor, and walls extending above the roof for producing a coffer dam,of wall trusses for the coifer dam walls, wall trusses for the wallsbeneath the roof, knee-braces extending from the roof to the lowermostchord of the trusses beneath the roof and knee-braces extending from theroof to the uppermost chord of the trusses arranged above the roof.

40. In a caisson, the combination with inclosing walls and a roof, ofcofler dam trusses extending above said roof and knee-braces extendingfrom the roof to the outermost chord of the coffer dam trusses.

41. In a caisson, the combinat on with upright concrete walls formedwith a cutting edge, and reinforcing trusses embedded in said cuttingedges.

42. In a caisson, the combination with concrete inclosing walls formedwith a cutting edge of a metallic truss embedded in such cutting edge.

43. In a caisson, the combination with concrete inclosing walls formedwith a cutting edge, of reinforcing trusses arranged at right angles andconnected together and embedded in said cutting edge.

44. In a caisson, the combination with concrete inclosing walls formedwith a cutting edge, of a metallic truss embedded in said cuttlng edgeand reinforcing bars connected to said truss and embedded within saidwalls.

45. In a caisson, the combination with concrete inclosing walls, formedwith a cutting edge, of a vertical truss embedded in said cutting edge,and a transversely disposed plate secured to said truss and arranged forconstituting the penetrating surface of the cutting edge.

46. In a caisson, the combination with inclosing walls having a cuttingedge, of a reinforcing open-web truss embedded in said cutting edge.

In testimony whereof I aflix my signature in presence of two Witnesses.

OLIVER CROMWELL EDWARDS, JR.

Witnesses:

HENRY CoLvrN, SAMUEL GORDON.

